Device for the continuous manufacture of artificial sponges,especially of regenerated cellulose



Dec. 30. 1969 P. A. J. BIBOST ISA-86,1 91 DEVICE FOR THE CONTINUOUSMANUFACTURE OF ARTIFICIAL SPONGES, ESPECIALLY OF REGENERATED CELLULOSEFiled June 20, 1967 3 Sheets-Sheet l A TTOR/VEf m h P w E M u o w m P 01 Dec. 30. 1969 P A. J. BIBOST 3,486,191

DEVICE FOR THE CONTINUOUS MANUFACTURE OF ARTIF AL SPONGES, ESPECIALLY 0FREGENERATED CELLULOS 3 Sheets-Sheet 2 Filed June 20, 1967 Dec. 30. 1969P. A. J. BIBOST 3,486,191

DEVICE FOR THE CONTINUOUS MANUFACTURE OF ARTIFICIAL SPONGES, ESPECIALLYOF REGENERATED CELLULOSE Filed -June 20, 1967 3 Sheets-Sheet 5 3,486,191EVICE FOR THE CONTINUOUS MANUFACTURE OF ARTIFICIAL SPONGES, ESPECIALLY FRE- GENERATED CELLULOSE Pierre Andr Joseph Bibost, Beanvais, France,assignor to N ovacel Societe Anonyme, Paris, France, a corporation ofFrance Filed June 20, 1967, Ser. No. 647,469

Int. Cl. 1329c 3/04 US. Cl. 18-5 18 Claims ABSTRACT OF THE DISCLOSURE Adevice for the continuous manufacture of artificial sponges obtained bythe electrical coagulation of a pulp consisting of viscose, reinforcingfibres and porositycreating material, said device comprising ahorizontal plate, rotatable and capable of receiving or forming anannular mould open at it upper portion, the mould being connected to asource of electric current and passing during its rotation in front offixed stations comprising a pulp-feeding station, pressing meansalternating with means for extracting the liquor exuded during thecoagulation of the pulp from said mould, means for re-cycling part ofthe liquor into the mould, said means being followed by an extractionstation at which the pulp arriving in a coagulated state is extractedfrom the mould by means of driving means external to said plate, amouldwashing station located between the feeding station and theadjacent extraction station being arranged to form a lock-chamber in themould.

The present invention relates to a device for the continuous manufactureof artificial sponges, especially of regenerated cellulose.

Devices are already known which are arranged for the continuousmanufacture of artificial sponges by the coagulation of a plup composedof viscose, reinforcing fibres, and porous material. Following onemethod of manfuacture, these sponges are produced by means of a devicecomprising a die with a vertical axis, extended by a sleeve having asection larger than the die, and which is provided with means intendedto ensure the coagulation of the pulp. These coagulation means areconstituted by electrodes and a large number of parallel fingers whichensure constant contact between the electrodes and the pulp. By thismeans, the electric current causes an increase in the temperature of thepulp and thus ensures its coagulation.

After the sleeve and beyond the electrodes, the roll of coagulated pulpfirst passes through a tank containing a bath composed of a solution ofsodium sulphate at 90- 100 C., and then through the usual washing andfinishing baths, together with a drying apparatus, after which the dryproduct can be shaped and cut-up.

Following another method which is also known for the continuousmanufacture of artificial sponges of regenerated cellulose, the pulp isformed into a roll in a device comprising a channel of insulatingmaterial, the walls of which are lined with metal plates and insidewhich circulates the upper side of an endless conveyor belt or rubber;the coagulation of the pulp, brought-up to a prenited States Patent 03,486,191 Patented Dec. 30, 1969 ICC determined point directly above thebelt is obtained electrically through the intermediary of movingelectrodes arranged along the lateral walls of the channel, theseelectrodes being in contact with the sides of the mass of pulp inmotion.

In a device of this kind, the electrodes are constituted by two seriesof contiguous metal plates which are fixed on chains with linkstravelling on the upper edges of the channel, the coagulated roll beingthen discharged on to a table, beyond the electrodes, and then subjectedto the usual finishing and drying means and finally to the shapingprocess.

In addition to the fact that they are of complicated construction, thesedevices do not give complete satisfaction, especially since, during itscoagulation, the pulp is subjected to displacements and other handlingwhich may lead to deformation and also may result in a finished producthaving an external appearance which leaves much to be desired.

The present invention has for its object to eliminate the drawbacksmentioned above, and proposes to this end a device which, in addition toa simple construction and robust structure, has numerous advantages.

According to the invention, the device for the continuous manufacture ofartificial sponges obtained by coagulation of a pulp composed ofviscose, reinforcement fibres and porous material, is especiallycharacterized in that it comprises at least one plate capable ofrotation and adapted to receive and/or to form at least one annularmould, open at its upper portion, the said mould being on the one handcoupled to a source of electric current, and on the other hand passingduring its rotation in front of fixed stations comprising respectively apulp-feeding station, pressing means alternating with means forextracting the liquid and means for re-cycling part of this latter intothe said mould, which are following by an extraction station at whichthepulp arriving in the coagulated state is extracted from the mould bymeans of carrying means external to the plate, while a washing stationfor the said mould is arranged between the feeding station and theneighbouring extraction station, and is adapted to form a lock-chamberin the said mould.

With this arrangement, it can immediately be seen that the use of arigid rotating mould passing in front of fixed stations permitscoagulation of the pulp which is stationary with respect to the mould.For this reason, the risk of deformation is eliminated and therefore thefinished product has an outer surface free from irregularities.

Other characteristic features and advantages of the invention willfurthermore be brought out in the description which follows below, givenby way of example, reference being made to the accompanying drawings, inwhich:

FIG. 1 is a diagrammatic plan view of the device according to theinvention, this device being seen from above.

FIG. 2 shows a perspective view of the feeding station;

FIG. 3 is a similar view, showing a pressing device;

FIG. 4 illustrates, also in perspective, the sprinkling and re-cyclingmeans;

FIG. 5 shows the extraction station for the formed roll from the mould,together with the roll-carrying station;

FIG. 6 illustrates the washing station for the mould.

In the preferred form of construction chosen and shown in FIGS. 1 to 6,the device according to the invention comprises a plate 10 capable ofrotation about a vertical axis 0. With the upper surface of this plateis associated an annular mould indicated generally at 11, which isconcentric with the axis of rotation. This mould has a U-shaped straighttransverse section, and is constituted as shown in FIG. 2 by a base 12of insulating material fixed to the plate, and by vertical metal walls13 and 14. Each of the walls is composed of a plurality of elements 15suitably curved, mounted end-to-end and connected together by means ofwaterproof and insulating expansion joints 16, the whole assembly thusformed constituting the mould proper 11.

The elements 15 of each of the walls of the mould are connected togetherelectrically by means of two-pole contactors shown diagrammatically at17 to a transformer 18 fixed for example in a central part of the plate10 and connected in any suitable manner to a source of electric currentwhich has not been shown.

At the upper portion (see particularly FIGS. 2 to 6), the vertical wallsof the mould are provided on their edges with gutters 19 and 20, thepurpose of which will be explained later. These gutters, of metal orinsulating material, are in communication through the intermediary oftubes 21 with a recovery tank arranged for example underneath the plate10.

The plate 10 is enclosed externally by a ring 22 which is fixed and onwhich are mounted the elements belonging to each of the stationsarranged immediately above the mould and at pre-determined positions.The position of the pulp-feeding station is shown at 23, while 24designates the pressing means; the liquid sprinkling means 25 aresupplied by the re-cycling means 26, while 27 indicates the extractionstation for the bar of material which arrives at this point in acoagulated state, while 28 shows the means for transferring the bar tothe finishing baths (not shown). Between this last station and the feedstation, there is provided a mould washing station 29.

Each of these units will now be described in greater detail, beginningwith the pulp-feeding station, more clearly shown in FIG. 2, from whichit can be seen that the pulp P is fed into the mould 11 by means of anendless screw 30 rotating inside a conduit 31 extended by a conduit 32which is elbowed twice, and the end section 33 of which is preferablyshaped in such manner as to have a direction tangential to the interiorof the mould at the same time being very close to the insulating base 12of the mould.

On the other end of the pulp-feeding station the direction of rotationof the plate (arrow F), are arranged pressing means 24a to 24g, thelatter being close to the extraction station 27. Each of these pressingdevices comprises (see FIG. 3) a roller 36 of insulating materialmounted radially above the mould and carried by a crossarm fixed to theouter ring 22. These rollers rotate freely and can slide in a verticalplane by means of slots 37, so that they remain continuously in contactwith the upper surface of the bar of pulp P.

Between the rollers 24a, 24b and 24d, 24e respectively are providedliquid distributors 25, which are supplied (see particularly FIG. 4) bymeans of pumps 26 which draw-in through a pipe 38 the liquor which isexuded from the pulp during the course of its coagulation. It should benoted that these pumps are arranged so as to recycle only a part of theexuded liquor into the distributors 25, the remaining part beingdirected towards the recovery tank, whereby the level of the liquor ismaintained and a circulation of this liquor is established in order tomake the coagulation medium uniform. This recycling is effected by meansof conduits 39 which lead mounted the extraction station 27, clearlyshown in HG.

5, and this is followed by. the transfer station 28 of the coagulatedbar. The extraction station, close the feed station, is made-up of ashoe 40 placed in the mould; this shoe is oscillating and is carried bymeans of a frame 41 pivoted on a stud carried by the outer ring 22. Thisshoe. made of insulating material, has an upwardly-sloping ramp 42followed by a fiat portion 43, while cheeks 44, 45, carried by the outerring are advantageously arranged to facilitate the transfer of the barextracted from the mould 11 to the driving means 28.

These latter means comprise a first pair of guiding rollers 46 and 47with smooth surfaces; these rollers. mounted one below the other, rotatefreely on horizontal spindles 48 carried by vertical brackets'49, fixedfor example on the ring 22.

On the other side of these guiding rollers are arranged pairs of rollerswith vertical axes, some with smooth surfaces, the other driving rollerswith fluted surfaces, which are arranged alternately. Two pairs ofdriving rollers 50 with fluted surfaces and two pairs of guiding rollers51 with smooth surfaces are thus mounted laterally to the bar which hasbeen formed; however, these driving means in one alternative form ofconstruction may only comprise driving rollers with fluted surfaces.

It should be noted that the driving rollers 50 are driven at a suitablespeed by means of one or more motors with speed-varying gear (notshown), the linear speed of these rollers being equal to the tangentialspeed of the mould.

Reference will now be made more particularly to FIG. 6 which shows thewashing station located in the space comprised between the feed station23 and the extraction station 27, This washing station comprises twoscrapers 53, 54 which are engaged in the mould 11, spaced apart andcarried on arms 55 fixed to the outer ring. These scrapers arepreferably of rubber and are in close contact with the inner walls 12,13, 14 of the mould, so as to ensure the cleaning of these walls by arubbing action. This arrangement creates a lock-chamber 56 in the mould,level with which is provided, on the one hand a distributor 57 for thewashing water and on the other hand, conduits 58 coupled by piping 59 toa suction pump 60.

During the operation of the device, that is to say when the mould isrotating, the distributor 57 for washing water is continuously supplied,while the suction pump 60 is in action, so that the washing water whichis in the lockchamber is constantly renewed during the rotation, whichthus provides effective cleaning of the walls of the chamber.

The operation of the device described above may be analysed in thefollowing manner.

The mould 11 being given a rotating movement by rotation of the plate10, the pulp P which is in particular composed of viscose, reinforcingfibres and crystals of sodium sulphate, is fed in at a constant rate offlow by the screw 30 and is distributed by the conduit 32, 33 to theinterior of the mould in the vicinity of the bottom 12, so as to avoidany reflux of the pulp towards the rear.

It will be observed that, due to the shape given to the pipe 32, 33, thecourse of the pulp is subjected to two changes in direction, whichproduces a de-orientation of the fibres in the pulp, the latter havingbeen considerably directed towards the upstream side by the effect ofthe feed-screw.

The pulp P moves with the mould 11 and thus follows a circular travel oflimited extent from the feeding station to the extraction station.During its movement, the pulp is traversed by an electric current whichis transmitted through the walls of the mould, acting as electrodes, andthis causes progressive coagulation of the said pulp.

During its coagulation, the pulp shrinks and becomes detached from thewalls of the mould after having effected part of its circular travel; itis at this stage that the pressing rollers 36 come into action and, bypressing on the coagulated bar, hold the latter down inside the mouldand keep it immersed in the exuded coagulation liquor.

The suction pumps 26 extract the excess coagulation liquor formed fromthe surface; this liquor is sent in part towards the recovery tank,while the remainder is recycled and distributed by the distributors 25over the pulp in course of coagulation. By virtue of the gutters 19 and20 on the edge of the mould, the contacts are protected from anypossible overflow of the liquor.

The bar of coagulated pulp is traversed by the electric current from thefeed station up to the extraction station, at which it must arrive inthe coagulated state, At this point, the bar is extracted from the mouldby the shoe 40 by means of the sloping ramp 42, and then it is guided bythe cheeks 44 and 45 and subsequently passes between the guiding rollers46, 47, from which it is taken and driven by the pairs of rollers 50, 51which lead it towards the usual washing and finishing baths.

It should be noted that the exuded liquor contained in the mould cannotpenetrate into the lock-chamber 56, the scrapers 53, 54 of which arearranged to form fluid-tight joints, both on the feed side and on theextraction side.

An asynchronous motor connected to a source of threephase current ispreferably employed to supply the transformer 18 through theintermediary of an alternator and a rotating contact. As regards themould elements 13, 14 which form the walls of this latter, they may beof any desired number; however, each wall of the mould is preferablymade-up of twelve elements. In the example described, the mould sectionis of U-shape; it will easily be seen that the mould elements may begiven an incurved profile or any other profile which enables a desiredshape of sponge to be obtained. This is obviously true also with regardto the bottom of the mould.

Furthermore, in order to prevent the production of curved blocks ofsponge, the diameter of the mould will preferably be greater than 3.50m., while the electrical supply may be obtained by transformation ofthreesphase current to hexaphase current, and then to single phase bymeans of rectifiers and a thyratron inverter.

In an alternative form of embodiment, the device may be of the multipletype. It may for example comprise a number of concentric moulds mountedon a single plate. Similarly, a number of plates provided with one or anumber of moulds may be superimposed on a common vertical driving shaft,each of the moulds, three for example, being connected to one phase of athree-phase current supply.

The device is advantageously surmounted by a canopy for drawing-out thegases.

Also in an alternative form, the evacuation of the liquors may beeifected by suction, and the circulation of these liquors may beeffected by means other than the pumps referred to, for example by meansof bucket elevators.

It will of course be understood that the invention is not limited to theforms of construction described, which may on the contrary form thesubject of modifications, without thereby departing from the scope ofthe invention.

What I claim is:

1. A device for the continuous manufacture of artificial sponges,including at least one horizontal plate mounted for rotational movement,said plate being provided with at least one annular mould open at itsupper part, said mould being coupled to a source of electric current toassist in coagulation of pulp in said mould, a plurality of fixedstations including means for feeding pulp to said mould, means forpressing pulp in said mould, means for extracting from said mould liquidexuded during coagulation of pulp in said mould, means for removing pulpfrom said mould including driving means external to said plate, meanslocated between said removing means and said feeding means for washingsaid mould, said mould passing with rotations of said plate in front ofsaid plurality of fixed stations.

2. A device as claimed in claim 1, in which said mould proper has astraight transverse section of U-shape.

3. A device as claimed in claim 1, in which the mould includes verticalwalls constituted by a plurality of metal elements end-toend, saidelements being coupled together by fluid-tight and insulating expansionjoints, and the bottom of said mould including a ring of insulatingmaterial.

4. A device as claimed in claim 3, in which each of the walls of saidmould is constituted by twelve elements.

5. A device as claimed in claim 1, in which the mould includesupstanding walls, the upper part of the walls including gutters arrangedto evacuate any overflow of liquid from the mould to a recovery tank.

6. A device as claimed in claim 1, in which said pulpfeeding meansincludes an endless screw rotatably mounted in a tube, said tube beingextended, beyond said screw, by a section elbowed first substantiallythrough downwards and secondly substantially at 90 in the direction ofrotation of said plate and said mould.

7. A device as claimed in claim 1, in which said pressing means areconstituted by rollers adapted to rotate freely, said rollers beingvertically displaceable in slides formed in a supporting arm, said armbeing rigidly fixed to a fixed support station adjacent the edge of saidplate.

8. A device as claimed in claim 1, in which said means for extractingfrom the mould the liquor exuded during the course of coagulationcomprise at least one suction pump provided with branches to re-cyclepart of the extracted liquid and directed part of said liquid to arecovery tank.

9. A device as claimed in claim 1, in which, beyond said removing means,means are provided to r ceive the bar of coagulated material includingguiding rollers having horizontal axes, vertically mounted rollersdriven in rotation and disposed laterally to said bar, at least some ofsaid rollers being provided with fluted surfaces.

10. A device as claimed in claim 1, constituted by a plurality ofsuperposed plates, each said plate comprising a plurality of concentricmoulds. 11. A device as claimed in claim 1 wherein said wash ing meansincludes arcuately spaced scrappers forming a lock in said mould andmeans for pumping liquid into and removing liquid from said lock.

12. A device for the continuous production of artificial spongeincluding:

(a) a rotably mounted annular mould,

(b) a stationarily mounted pulp feeding unit positioned adjacent saidmould,

(c) at least one stationarily mounted pulp pressing unit positioned tooverlie said mould, and

(d) means stationarily mounted adjacent said mould for removing pulpfrom the mould upon rotation of said mould through an arc ofapproximately 270.

13. A device as defined in claim 12 further including means connected tosaid mould and passing an electrical current through pulp in said mould.

14. A device as defined in claim 12 wherein said mould is horizontallypositioned for rotation about a vertical axes, the mould being coaxialwith the axes of rotation, the mould having an open upper surfacethrough which pulp may be fed from the feeding means and removed by theremoving means after said mould is rotated through an arc ofapproximately 270.

15. A device as defined in claim 14 wherein the pulp pressing unitincludes a roller having an axis parallel to the radius of the annularmould and mounted for free rotation and vertical movement.

16. A device as defined in claim 14 further including liquid removingmeans positioned adjacent the open portion of the annular mould forremoving liquid from said mould and recycling a portion of the liquidback to the mould and a portion of the liquid to a recovery tank.

17. A device as defined in claim 14 wherein said annular mould ishorizontally mounted coaxial with its vertical axes of rotation andhaving an open upper 7 8 surface with troughs adjacent each side of theupper 2,441,235 5/1948 Blair et al. surface to receive any overflow fromsaid mould. 3,174,887 3/1965 Voelker.

18. A device according to claim 17 wherein electrodes 3,215,581 11/1965Carlson et al. are connected to said mould to transmit an electricalcur- 3,336,631 8/ 1967 Smith. rent through any pulp positioned withinthe mould. 5 3,336,632 8/1967 Smith.

References Cited WILLIAM J. STEPHENSON, Primary Examiner UNITED STATESPATENTS 1 2,395,920 3/1946 Grotenhuis. 10 26

